Our goal is to advance understanding of the role of nutrition during the first 1000 days of life (conception to age 2y), a critical and vulnerable phas in brain development, on intellectual and other disabilities, as well as on schooling. We propose a study of the long term effects of the 1959-61 Chinese famine, the largest in human history with up to 30-50 million deaths. The famine provides a quasi-experimental setting for testing effects of exposure to prolonged and severe famine on cognitive development in the context of chronic undernutrition and poverty, the context common to most famines in human history and to poor populations in both developed and developing countries. We propose to use the data from the China Second National Survey on Disability (CSNSD), the most up-to-date national survey on disability in China. We will apply a robust difference-in- difference estimator to isolate the famie impact from other potential confounding factors using a novel approach to measuring the intensity of the Chinese famine at county level. We will study birth cohorts born before (1956-58), during (1959-61) and after the famine (1962-1964) and explore how impact varies by timing of exposure to the famine, sex and urban/rural origin. A total of 174,988 men and 173,688 women will be included in our study. Our general hypothesis is that exposure to the famine during the first 1000 days of life, but not later, leads to a) higher risk of intellectual disabiliy and visual, speech, hearing, psychiatric, and physical disabilities, and less schooling; b) larger impact among men than women due to the greater biological vulnerability of men; c) larger impact among rural than urban residents due to the greater severity of the famine in rural areas. Our research team provides extensive expertise in Chinese famine and cohort research, disability research, and design and use of the CSNSD data. We expect our findings to enrich the literature regarding nutrition and cognitive development and possibly to support the importance of improving nutrition in pregnancy and early childhood among high risk population in both poor countries as well as developed countries such as the US. PUBLIC HEALTH RELEVANCE: The project will assess the impact of exposure to the Chinese famine of 1959-61 during pregnancy and the first 2 years of life on adult intellectual disability, visual, speech, hearing, psychiatric, and physical disabilities, and schooling. This study will contribute to the knowledge of effects of exposure to prolonged and severe famine on cognitive development in the context of chronic undernutrition and poverty, the context common to poor populations in both developed and developing countries.